Try Artstor and the library catalog. On the Library's homepage you will see in the center of the page Research Guides and Course Guides. Click on the Research Guides link, which will bring you to a list of Research Guides. Choose the Architecture Reasearch Guide and select the Images page/tab. You will find suggestions for conducting image searches as well as resources in which to search.
Please talk with a librarian if you are not having success in your searches, we're here to help you! I'm including quick links below.